32Mbit Flex Protocol And Ibafob-D Network; Data Amount And Sampling Rate - IBA ibaFOB-D Manual

ibaFOB-D
11

32Mbit Flex protocol and ibaFOB-D network

The ibaNet 32Mbit Flex protocol (referred to as "Flex protocol") is a manufacturer specific
data transfer protocol by iba AG. This protocol serves to transfer measurement and con-
figuration data via FO connections between different iba devices. The PC boards of the
ibaFOB-D/ibaFOB-Dexp and ibaFOB-io-ExpressBoard series, the ibaFOB-io-USB
adapter as well as some devices for data acquisition support this protocol.
11.1

Data amount and sampling rate

The Flex protocol works with a data transfer rate of 32 Mbit/s and supports up to 15
"Flex-capable" devices connected in a ring topology.
With 32Mbit Flex, the data amount and the sampling rate can be selected in a flexible
way. The data amount transferred per cycle depends on the sampling rate. Generally,
the following applies: The less data are transferred, the higher is the possible sampling
rate.
For the signals to be measured, sampling rates of 500 Hz to 100 kHz can be realized,
which correspond to a timebase from 10 µs up to 2 ms. The maximum sampling rate also
depends on the acquisition device and can be found in the device manual. In ibaPDA
you can select even smaller sampling rates down to 1 Hz. This corresponds to a time-
base of 1000 ms. In this case, the timebase in the Flex ring is set to 2 ms and in ibaPDA
a subsampling is carried out. Data which is not relevant for the configured sampling rate
is disboarded by ibaPDA.
With 32Mbit Flex, up to 4060 Bytes per cycle can be acquired and recorded depending
on the sampling rate.
For the max. possible data amount of 4060 Bytes, the cycle time (timebase) is up to
1.4 ms. In the following table, you find reference values for the relation between cycle
time and the max. transferable data amount per cycle. If you want to get more values,
especially if several devices are connected in a Flex ring topology, iba recommends us-
ing the simulator integrated in ibaPDA, see chapter 8.1.6.2.
Timebase
1.4 ms
1.0 ms
0.5 ms
0.025 ms
The following data types are supported: BYTE, WORD, DWORD, INT, DINT, FLOAT and
DOUBLE in Big/Little Endian format. These data amounts represent the limit values for
the overall data amount on a Flex ring that can be transferred via an FO link.
Manual
Max data amount
4060 Bytes
3100 Bytes
1540 Bytes
64 Bytes
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